HIV target cells in Schistosoma haematobium-infected female genital mucosa

The parasite Schistosoma haematobium frequently causes genital lesions in women and could increase the risk of human immunodeficiency virus (HIV) transmission. This study quantifies the HIV target cells in schistosome-infected female genital mucosa. Cervicovaginal biopsies with and without schistosomiasis were immunostained for quantification of CD4(+) T lymphocytes (CD3, CD8), macrophages (CD68), and dendritic Langerhans cells (S100 protein). We found significantly higher densities of genital mucosal CD4(+) T lymphocytes and macrophages surrounding schistosome ova compared with cervicovaginal mucosa without ova (P = 0.034 and P = 0.018, respectively). We found no increased density of Langerhans cells (P = 0.25). This study indicates that S. haematobium may significantly increase the density of HIV target cells (CD4(+) T lymphocytes and macrophages) in the female genitals, creating a beneficial setting for HIV transmission. Further studies are needed to confirm these findings and to evaluate the effect of anti-schistosomal treatment on female genital schistosomiasis.     

HIV target cells: effect of their infection by HIV on the pathogenesis of AIDS

Pathogenesis of HIV infection and expression of retroviral proteins are gradually being elucidated. Antibody to HIV is a marker of past or present viral infection. The virus can be isolated from cultured lymphocytes of seropositive but not seronegative patients. Sero-epidemiological studies show that the majority of infected patients are asymptomatic carriers without biological sign of immune depression. Some then show immune abnormalities such as a decrease of CD4 cells in the blood; some patients present with lymphadenopathies or signs of AIDS-related complexes. Frank AIDS is a late stage of the disease. Some cofactors increase the immunodeficiency and then accelerate the passage from asymptomatic carrier to persistent generalized lymphadenopathies or AIDS by spreading the virus into target cells, susceptible T4 cells, bone marrow precursors, or brain. These AIDS patients then present with opportunistic infections and/or malignancies like Kaposi's sarcoma, lymphoma, and/or brain diseases (dementia or encephalitis).     

Pulmonary infections in children with HIV infection

The epidemic of pediatric acquired immunodeficiency syndrome (AIDS) in the United States, which peaked during the mid-1980s and early 1990s, was characterized by a variety of opportunistic infections in children infected with human immunodeficiency virus (HIV), often as the presenting illness of their HIV infection. Pneumocystis carinii pneumonia (PCP) during infancy was responsible for significant morbidity and mortality, followed by many other opportunistic infections, including recurrent, serious bacterial infections; disseminated cytomegalovirus infection; and disseminated Mycobacterium avium complex (MAC) infection. Many of these infections involve the lower respiratory tract either as a primary site of infection or as one of the sites involved in disseminated disease. Since the mid- to late 1990s, the pediatric HIV epidemic in the United States has witnessed a dramatic decrease in the frequency of most opportunistic infections and other severe manifestations of HIV infection in children, primarily because of lower rates of mother-to-child HIV transmission, development and implementation of guidelines for PCP prophylaxis, and availability of highly active antiretroviral therapy. Far fewer children are at risk for clinical progression of HIV disease and for opportunistic infections. Despite these successful trends, pulmonary opportunistic infections and pulmonary disease remain common clinical manifestations of pediatric HIV disease.     

Mechanism by which the lectin actinohivin blocks HIV infection of target cells

Various lectins have attracted attention as potential microbicides to prevent HIV transmission. Their capacity to bind glycoproteins has been suggested as a means to block HIV binding and entry into susceptible cells. The previously undescribed lectin actinohivin (AH), isolated by us from an actinomycete, exhibits potent in vitro anti-HIV activity by binding to high-mannose (Man) type glycans (HMTGs) of gp120, an envelope glycoprotein of HIV. AH contains 114 aa and consists of three segments, all of which need to show high affinity to gp120 for the anti-HIV characteristic. To generate the needed mechanistic understanding of AH binding to HIV in anticipation of seeking approval for human testing as a microbicide, we have used multiple molecular tools to characterize it. AH showed a weak affinity to Manα(1–2)Man, Manα(1–2)Manα(1–2)Man, of HMTG (Man8 or Man9) or RNase B (which has a single HMTG), but exhibited a strong and highly specific affinity (K_d = 3.4 × 10⁻⁸ M) to gp120 of HIV, which contains multiple Man8 and/or Man9 units. We have compared AH to an alternative lectin, cyanovirin-N, which did not display similar levels of discrimination between high- and low-density HMTGs. X-ray crystal analysis of AH revealed a 3D structure containing three sugar-binding pockets. Thus, the strong specific affinity of AH to gp120 is considered to be due to multivalent interaction of the three sugar-binding pockets with three HMTGs of gp120 via the “cluster effect” of lectin. Thus, AH is a good candidate for investigation as a safe microbicide to help prevent HIV transmission.     

Bacterial infections in children with HIV/AIDS

HIV/AIDS affects over 850,000 children in Africa. Bacterial infections are frequent in this group of children. Pneumonia, meningitis and septicaemia are especially common, recurrent and most often caused by Streptococcus pneumoniae. Salmonella spp are the most frequently isolated causative agent of septicaemia in malarial areas. Soft tissue, eye and oral infections have a higher incidence in HIV-infected than uninfected children. In all instances the causative agents are not dissimilar from those that cause disease in HIV-uninfected children, but the mortality is greater. Increased bacterial resistance to first line antibiotics has been reported and the use of cotrimoxazole prophylaxis may further influence the resistance pattern of common bacteria.     

多发性骨髓瘤患者社区感染和院内感染间的差异

目的:总结多发性骨髓瘤(MM)患者社区感染和院内感染的特点,了解2类感染间的差异,以期对2类感染在抗生素的选择上有所帮助。方法:回顾性分析近5年来我院多发性骨髓瘤(MM)患者社区感染和院内感染情况。结果:MM患者47例,发生感染20例,占42.55%,其中院内感染16例(80%),痰培养铜绿假单胞菌ESBLs( )1例、肠球菌1例、白色念珠菌1例、光滑念珠菌1例;中段尿培养大肠埃希氏菌ESBLs( )1例、类星形念珠菌1例;血培养肺炎链球菌1例;社区感染4例(20%);肺结核并铜绿假单胞菌ESBLs(-)1例、铜绿假单胞菌ESBLs(-)1例、白色念珠菌1例。结论:我院近5年MM患者的感染以院内感染为主,细菌与真菌约各占一半,细菌以ESBLs阳性为主;社区感染中细菌、真菌、结核均可出现,细菌感染ESBLs为阴性。     

HIV dynamics and immunosenescence

Three differential equations modelling HIV virion, and infected and uninfected immune-cell densities during acute and chronic phases of infection underlie in-vivo HIV viral dynamics models. Adding a fourth equation that simulates immunosenesence through the drawdown of a stem-cell reservoir permits the phase of full-blown AIDS to be incorporated in the model. This greatly enhances the utility of the model in designing interventions and explains why time-to-full-blown AIDS decreases with age at infection.     

Dengue infections in HIV patients

A retrospective review of hospital admission records was conducted on patients who were admitted to the Communicable Disease Center (CDC)/Tan Tock Seng Hospital, Singapore from 1 January 2004 to 31 December 2005. There were 5 HIV patients who were admitted with dengue infection during the study period. Their symptoms were generally mild and recovery was uneventful. None of the patients developed dengue hemorrhagic fever or dengue shock syndrome. The symptoms and signs of dengue infection in HIV patients are nonspecific. It is important for healthcare workers to maintain a high index of suspicion in order to make the diagnosis. Interactions between pathogenesis pathways or with antiviral treatments may have contributed to the apparently less severe dengue infections in HIV patients. This observation needs to be explored further.